1) Slow startup. I have taken out as much as I put in which automatically starts, except for firewall (Zone alarm) and anti-virus (Avast home edition), and spywareblaster.
There are probably other processes which automatically start that I don't need. I don't know how to identify them. I did a spybot S&D scan earlier today.
It found a tracking cookie, which I fixed. Windows Updates also ran, installing stuff, which literally took hours and hours to run.

2) I have almost no disk space left. About 800 MB (out of 10 GB). WHERE did it all go? Are there temporary files from MS windows updates that I need to clean up? Any other temp files I need to hunt down and eliminate?

Logfile of HijackThis v1.99.1
Scan saved at 5:14:53 PM, on 3/27/2007
Platform: Windows XP SP2 (WinNT 5.01.2600)
MSIE: Internet Explorer v7.00 (7.00.5730.0011)
Running processes:
C:\WINDOWS\System32\smss.exe
C:\WINDOWS\system32\winlogon.exe
C:\WINDOWS\system32\services.exe
C:\WINDOWS\system32\lsass.exe
C:\WINDOWS\system32\svchost.exe
C:\WINDOWS\System32\svchost.exe
C:\WINDOWS\system32\spoolsv.exe
C:\Program Files\Alwil Software\Avast4\aswUpdSv.exe
C:\WINDOWS\System32\atievxx.exe
C:\Program Files\Alwil Software\Avast4\ashServ.exe
C:\WINDOWS\System32\svchost.exe
C:\WINDOWS\system32\ZoneLabs\vsmon.exe
C:\WINDOWS\System32\wbem\wmiapsrv.exe
C:\WINDOWS\Explorer.EXE
C:\Program Files\Alwil Software\Avast4\ashMaiSv.exe
C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
C:\Program Files\Zone Labs\ZoneAlarm\zlclient.exe
C:\WINDOWS\system32\ctfmon.exe
C:\Program Files\Alwil Software\Avast4\ashWebSv.exe
C:\WINDOWS\system32\wuauclt.exe
C:\Program Files\Mozilla Firefox\firefox.exe
C:\Documents and Settings\All Users\Documents\SecurityDownloads\HijackThis.exe
C:\Program Files\Alwil Software\Avast4\setup\setup.ovr
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Bar = http://cgi.verizon.n...mp;bm=ho_search
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Page = http://my.juno.com/s...ch?r=minisearch
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = http://go.microsoft....k/?LinkId=69157
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Search_URL = http://go.microsoft....k/?LinkId=54896
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Search Page = http://go.microsoft....k/?LinkId=54896
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Start Page = http://go.microsoft....k/?LinkId=69157
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,SearchAssistant = http://my.juno.com/s...ch?r=minisearch
R1 - HKCU\Software\Microsoft\Internet Explorer\SearchURL,(Default) = http://my.juno.com/s...ch?r=minisearch
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Window Title = Microsoft Internet Explorer provided by Verizon Online
R1 - HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings,ProxyOverride = 127.0.0.1
R3 - URLSearchHook: URLSearchHook Class - {37D2CDBF-2AF4-44AA-8113-BD0D2DA3C2B8} - C:\Program Files\JUSearch\SearchEnh1.dll
N3 - Netscape 7: user_pref("browser.startup.homepage", "http://home.netscape.com/"); (C:\Documents and Settings\Linda\Application Data\Mozilla\Profiles\default\b12gue23.slt\prefs.js)
N3 - Netscape 7: user_pref("browser.search.defaultengine", "http://www.google.com/"); (C:\Documents and Settings\Linda\Application Data\Mozilla\Profiles\default\b12gue23.slt\prefs.js)
O2 - BHO: AcroIEHlprObj Class - {06849E9F-C8D7-4D59-B87D-784B7D6BE0B3} - C:\Program Files\Adobe\Acrobat 6.0\Reader\ActiveX\AcroIEHelper.dll
O2 - BHO: (no name) - {53707962-6F74-2D53-2644-206D7942484F} - C:\PROGRA~1\SPYBOT~1\SDHelper.dll
O4 - HKLM\..\Run: [Zone Labs Client] "C:\Program Files\Zone Labs\ZoneAlarm\zlclient.exe"
O4 - HKLM\..\Run: [avast!] C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
O4 - HKLM\..\Run: [ZoneAlarm Client] "C:\Program Files\Zone Labs\ZoneAlarm\zlclient.exe"
O4 - HKCU\..\Run: [ctfmon.exe] C:\WINDOWS\system32\ctfmon.exe
O4 - Global Startup: SpywareBlaster.lnk = C:\Program Files\SpywareBlaster\spywareblaster.exe
O8 - Extra context menu item: E&xport to Microsoft Excel - res://C:\PROGRA~1\MICROS~2\Office10\EXCEL.EXE/3000
O9 - Extra button: Control Pad - {28D44DAD-D1FC-4d4f-BB1B-ADF037C8DDBC} - C:\Program Files\Verizon Online\Verizon Online Control Pad\VerizonControlPad.Exe
O9 - Extra 'Tools' menuitem: Control Pad - {28D44DAD-D1FC-4d4f-BB1B-ADF037C8DDBC} - C:\Program Files\Verizon Online\Verizon Online Control Pad\VerizonControlPad.Exe
O9 - Extra button: (no name) - {e2e2dd38-d088-4134-82b7-f2ba38496583} - %windir%\Network Diagnostic\xpnetdiag.exe (file missing)
O9 - Extra 'Tools' menuitem: @xpsp3res.dll,-20001 - {e2e2dd38-d088-4134-82b7-f2ba38496583} - %windir%\Network Diagnostic\xpnetdiag.exe (file missing)
O9 - Extra button: Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\Program Files\Messenger\msmsgs.exe
O9 - Extra 'Tools' menuitem: Windows Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\Program Files\Messenger\msmsgs.exe
O11 - Options group: [INTERNATIONAL] International*
O16 - DPF: {6E32070A-766D-4EE6-879C-DC1FA91D2FC3} (MUWebControl Class) - http://update.micros...b?1171478552459
O16 - DPF: {8AD9C840-044E-11D1-B3E9-00805F499D93} (Java Runtime Environment 1.4.1_02) -
O16 - DPF: {CAFEEFAC-0014-0001-0002-ABCDEFFEDCBA} (Java Runtime Environment 1.4.1_02) -
O20 - Winlogon Notify: WgaLogon - C:\WINDOWS\
O23 - Service: avast! iAVS4 Control Service (aswUpdSv) - Unknown owner - C:\Program Files\Alwil Software\Avast4\aswUpdSv.exe
O23 - Service: avast! Antivirus - Unknown owner - C:\Program Files\Alwil Software\Avast4\ashServ.exe
O23 - Service: avast! Mail Scanner - Unknown owner - C:\Program Files\Alwil Software\Avast4\ashMaiSv.exe" /service (file missing)
O23 - Service: avast! Web Scanner - Unknown owner - C:\Program Files\Alwil Software\Avast4\ashWebSv.exe" /service (file missing)
O23 - Service: TrueVector Internet Monitor (vsmon) - Zone Labs, LLC - C:\WINDOWS\system32\ZoneLabs\vsmon.exe