Windows XP Home Computer Won't Boot Up

I had been getting help on a second home computer from Ken545 at the HJT Logs and Spyware/Malware forum and had gotten that machine fixed. Then I decided to try to prevent a malware attack on a second computer (which had been running OK) and now the second computer won't boot up properly. It hangs up at the empty desktop showing only the background photo and no icons. The actions that I took on this machine just before this problem started were: I downloaded and installed CCleaner and ran the Cleaner tool and the Issues Scan (backing up the registry) and then installed the latest Microsoft Windows security update that had automatically downloaded to the computer. When I rebooted immediately after performing both these tasks, the system did not reboot normally. It hung up at the empty desktop. I booted up in Safe Mode and tried System Restore (which said that it accomplished the restore successfully) to a time before CCleaner installation but got the same problem on a normal reboot. Then I tried System Restore to the time after CCleaner had run but before the M/S security update installation. Still no change. Then, after booting up in Safe Mode, I went back to the registry backup file in CCleaner and double clicked on it. When the question came up "Are you sure you want to add these values to the registry?" I answered yes. Then I tried a normal reboot, but still no change in the problem. I have tried to reboot with the last known good configuration but to no avail. I'm afraid some essential system files were somehow changed or deleted, but have no idea how this could have happened. Everything appeared to work just fine throughout the CCleanup and Windows Update processes, but the reboot failed. I even tried letting Windows try to boot up overnight, but it was still hung up in the morning. I have tried again this morning several times to reboot but each time I get the same result. I can only boot up in safe mode or safe mode with networking. How do I get my machine back to normal. I'm out of ideas. Help!!!!

Ok, do you have a Windows XP installation cd?

If so, grab it and keep it handy. First, click right here to download Win98 startup disk. Find you a floppy and put it in A: (may have to format the floppy) then click on the file you just downloaded. Its self-extracting and will create the disk for you. After the disk is finished, put your Windows installation cd in the cd drive and with the floppy also in drive A: reboot. The first menu that will come up, choose "Start Windows with CD=ROM support"…then watch it till it gives you the C:\ prompt, right before it does it will tell you what drive letter your cd drive is. Then.. at the prompt..type D:\ (or whatever drive it told you your cd-rom was) and press enter. You will then be in your cd-rom's disk directory with the prompt accordingly. Now, type (or copy and paste) this–> SFC /scannow and the press enter (make sure you put a space between "SFC" and "/sccanow").

Let that do its thing. It may take a little bit. Afterwards post back.