Restarts with a Compaq Presario S6020wm

I'm taking a look at a pc problem for a friend of my son, so far HW wise it seems ok, I cleaned and remounted the cpu/hsf with AS5 so it should be happy.
I can run the pc with Puppy Linux CD all day so its not a heat or PSU or RAM issue.
I ran a WD diag on it and it passed with no problems, so it doesnt seem to be a hdd issue.
OK well the problem is when you get to the log in screen it just reboots over and over again, not even giving you enough time ot sign in.
I can go into safe mode but windows is messed up bad, cant access any drives, when i go to start>programs, it says empty seems to lock up and acts unresponsive.
I'm assuming at this point that windows is messed up either by virus/trojan/hijacker, etc. or by major user error., My son said something about the internet being messed up and getting a lot of popups etc.
Because its an HP/Compaq I'm thinking of doing either a non-destructive sys restore or maybe trying to get to a windows restore point, any other ideas out there.
BTW of course there are no restore disks, so i would either have to make them off the pc or order them from Compaq, I'm hoping the built in restore partitions didnt get damaged.

 

bump it, bump it good