a virus or a hardware problem??

Hi.Im running windows xp sp3,1.5gb of ram on an emachine....ok.this is my problem. sometimes when i get on the internet my scrollbar will suddenly drop all the way to the bottom. i can not scroll back up the page.my scroll bar starts to shake when i do and the page itself gets flickery.i have to close out of the browser. Then the rest of my computer starts acting funny.I try to log out,because thats the only way to fix the problem.But when i log out and get to the password box,the password box goes haywire and fills in a bunch of dots by itself as if i were typing it in myself.then sometimes it wont let me log out or shutdown.i have to do the manual shutdown from the power button.the problem is fixed once i reboot for awhile anyway. this only happens when im surfing the internet,not when im just browsing my computer,and it doesnt do it all the time.about once or twice a day i think.i have scanned this computer using malware bytes,microsoft safety scanner,norton power eraser,super anti spyware.and TDSSKiller.They all came up empty.Im beginning to wonder if this is causing the other problem that im having which is this>>... (Your computer was not able to renew its address from the network (from the DHCP Server) for the Network Card with network address 00219B5752E8. The following error occurred:
The semaphore timeout period has expired. . Your computer will continue to try and obtain an address on its own from the network address (DHCP) server.).This is driving me nuts!!!..lol.im using firefox 5.0,mozilla firefox yahoo edition 1.9..im running windows xp sp3 with 1.5gb of ram...ive also tried using different browsers,however it seems it doesnt matter what browser im using,it still does this..i have checked all my drivers and they seem to be fine,thinking it might be ah hardware problem.however,it is hard to up date this machine considering its an emachine and almost impossible to find updated drivers.everything looks good in device manager though.

 

i have updated all my drivers to the best of my abilities using the latest version of "Driver pack solution" This seems to be the only solution to finding drivers for this machine.It found many updates.we will see what happens.will get back to yahs when and if the problem continues to happen and go from there.

 

i guess its no such luck.im still having the same problem even after updating drivers

 

Hi,

Do you have an extra keyboard to try? I think the first thing to rule out is that the Page Up/Down, Home/End and down arrow key are not sticking. Any of those keys sticking would cause the browser symptoms.