cannot bootscan, cannot install malwarebytes - please help?

[lct]

Hello,

The other day Avast v4.8 found two things when I accessed a website and ran my mouse over a tab (these are from the log, dated 4/8):

JS: Prontexi-AM(Trj)
JS: IllredirAQ(Trj)

Now my computer (running WinXP) is really slow, will not go to websites at all and when I try to start it, it keeps restarting but never gets to the desktop unless I keep pressing the F8 key (then it works with no problem).

Last night I tried to do a bootscan in Avast v4.8 (which I thought was up-to-date) but it aborted about 1/3 of the way through. I tried to install Avast v5 (downloaded at the library yesterday); it would not. I tried to install Malwarebytes (downloaded at the library yesterday), it hangs at the "Registering files" screen (I tried three times).

What else can I try? Oh - forgot to mention I have dial-up, so the online scanners always time out on me; I've tried them before  .

Thank you ~

[Pondus]

Hitman Pro 3 - Second Opinion Malware Scanner http://www.surfright.nl/en/hitmanpro
How to start Hitman PRO in Force Breach mode http://hitmanpro.wordpress.com/2010/03/16/hitman-pro-in-force-breach-mode/

Dr.Web® LiveCD http://www.freedrweb.com/livecd/
How does it work? http://www.freedrweb.com/livecd/how_it_works/

[lct]

Thanks very much, I will try these!

[sg09]

@lct
I think you can try the installation of malwarebytes at safe mode...

[lct]

Hitman Pro 3 - Second Opinion Malware Scanner http://www.surfright.nl/en/hitmanpro
How to start Hitman PRO in Force Breach mode http://hitmanpro.wordpress.com/2010/03/16/hitman-pro-in-force-breach-mode/

Dr.Web® LiveCD http://www.freedrweb.com/livecd/
How does it work? http://www.freedrweb.com/livecd/how_it_works/

Thank you Pondus, I used Hitman Pro 3.5 last night and it really helped.