Computer Freezing & Unwanted Toolbars

I have a Dell Dimension 2350 with Windows XP operating system. For the past 5 days my computer has been freezing, sticking badly and two unwanted toolbars appeared suddenly. One, a "Yahoo!" toolbar, I went in and deleted the file. The other is an unknown with the words "X Remove Toolbar" on the extreme left button, but when I click on it, the page redirects to a "http://searchlink.." or "http://directlink…" website. I cannot locate the file in order to delete whatever is causing this to happen. My desktop icons just disappear whenever I click on the internet connection, if I am on a shared user page and try to shut down the computer from there, the icons disappear and only the wallpaper remains with no computer function at all, mouse, Cntrl-Alt-Del, nothing. I just changed over from dial-up connection to DSL today and after the technician left and I was on for about 2 hours, the DSL started slowing down and now the computer just freezes. I have to shut of the power now to cut the computer off. Also, since 5 days ago, when I am browsing on the internet or typing an e-mail and click a back button or link or whatever the browser closes and I lose everything. What do I need to do inorder to stop this madness?

well to help weed out malware you can do this, it requires two downloads.
ewido and spybot search and destroy. if you have either one of these already update them as well as your antivirus software– if not download them install and update, but dont run them yet, we will do that in SAFE MODE:

EWIDO:
1. Download Ewido and install
Ewido Security Suite. It is a free trial version of the program:

http://www.ewido.net/en/download/

2. Install ewido security suite
3. Launch ewido, there should be an icon on your desktop double-click it.
4. The program will now go to the main screen

You will need to update ewido to the latest definition files.

1. On the left hand side of the main screen click update
2. Then click on Start Update

The update will start and a progress bar will show the updates being installed.

SPYBOT SEARCH AND DESTROY:

http://www.safer-networking.org/en/index.html

Install the program and launch it.

Go to Start > Programs >Spybot > Search & Destroy and choose Spybot S&D

Close ALL windows except Spybot S&D
Click the button to "Search for Updates" and download and install the Updates.
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ok now boot computer into safe mode. you reach safe mode by tapping the f8 key during a reboot. chose the first option– safe mode
once in safe mode launch ewido and let it scan

Once the scan has completed, there will be a button located on the bottom of the screen named Save report
Click Save report.
Save the report .txt file to your desktop.

next run spybot search and destroy, last–run your antivirus software.
also in safe mode do this;

Click Start>Run then type %temp%
Hit OK. Delete all the files you can.

Empty your Temp folders. Go to Start > Run and type:cleanmgr. Windows will scan. When done check these 3 and press *ok* to remove:

Temporary Files
Temporary Internet Files
Recycle Bin
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reboot computer once, see if things improve….shelf life