Shield with exclamation mark in lower right corner of screen

[lama2]

It has taken over my computer. It changes my home page setting to google. Keeps popping up warning boxes, trying to get me to download anti-virus software. at first it took away all internet imgages but it seems that I have corrected that for now, anyway, but strange things are happening, and it seems to be related to that shield with the exclamation point in it.

 

[LookinAround]

Follow the malware removal steps you find by clicking here

 

[lama2]

UPDATE: Can't boot windows from HD or CD ROM

When i turn on comp. it goes to desktop but no processes start, just blank screen. I have gone to BIOS to set boot to CD ROM and it won't recognize the D drive. Also when i try to manually go to D drive from c prompt it wont recognize. Also messages say windows xp disk is not formatted correctly but when I put the Windows xp disk in another computer, Windows install comes up normally.

When it tries to boot an svc application error box says can't write to memory. I've run CHKDSK from safe mode, and it did not show errors. I just want to format and reinstall, but need help if it won't recognize the windows XP cd. Any help would be greatly appreciated.