computer freezing

Hi
I have an Acer Aspire desktop running Vista Home Premium. It is about 18 months old.
Today I downloaded Bullzip PDF printer and shortly afterwards the PC started freezing. I have uninstalled Bullzip and done 3 system restores to earlier dates. I have tried runnning antivirus scans and spyware scans but it never gets to the end of any of them before freezing. I have tried disconnecting most of the peripherals and have tried starting it in Safe Mode but nothing seems to help
It also sometimes freezes during the early stages of booting up. When it freezes the image left on the screen is often a bit blurred.
I have run out of ideas.
Please can anyone help?
Thanks

 

Hi there charliemp i think you may have become infected, so i suggest you click on this link http://forums.majorgeeks.com/showthread.php?t=35407 and then follow all the instructions, then post the logs asked for into the malware forum, along with a full explanation of what you where doing when this occured as you have done so here, after you do that please be patient, as the malware fighters do get busy, but will get round to sorting you out, also if there is anything that dosen't work when following the instructions, don't worry just keep going, but make sure you follow the instructions properly i:e read them very carefully.

Good Luck Rusty !