Continuous Reboot

Help!!!, I installed avast 4 free home edition a couple of days ago on my XP Pro SP2 system. My computer rebooted, a blue screen came up and avast did a virus scan. It said that it did not find any viruses and it rebooted my computer. This time a blue screen comes up and says that XP must scan system drive due to hard drive inconsistency recommend scan.

A couple of sentences talking about a certain dumpfile was truncated and then it just reboots again. I can’t get to a XP login screen…help.

Can you boot in Safe Mode (repeatedly press F8 while booting)?
http://support.microsoft.com/default.aspx?scid=kb;en-us;315222

There should (could) have a possibility of disabling automatic restart (the just reboots again behavior).
By disabling the automatically restart on system failure feature, you are able to read what messages appear on the blue screen and can, if necessary, pass the information on to your technical support person or post here.
It’s important the error numbers and the error message there.

Do you have any other antivirus installed in this computer?
Which firewall are you using?

Thanks for the help. I did an F8 and then Last Known Good. No more reboots.