Did you do the reformat yourself 18 months ago? You said, "It came back", as if it was done elsewhere, in a repair shop, etc.
Reformat does that. It reformats the hard disk and wipes it clean. There is another option to "Repair Install". This attempts to replace damaged system files without wiping the whole hard disk clean. Perhaps that is what you did 18 months ago?
You say you have the XP CD, but where is the Drivers CD? Your display problem sounds like you haven't finished installing all the drivers yet, like the video drivers.
Mark
I have a Dell Inspiron 1150 with Windows XP Home edition. About 18 mths ago I reformatted the hard drive and had no real problem. It came back as it was new. I had reason to do it again recently and for some reason it wiped absolutely everything off even the programs that were installed when the computer was new (2004). It tried to read and install Windows 95 (I have no idea why) but failed miserably. I have reinstalled XP with a CD but for some reason cannot reset the screen resolution and in the browser windows it shows roughly 25% of the page. It does the same in Internet Explorer, Firefox and Google Chrome. If anyone has any ideas please come back to me.

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