New monitor problems - type size and image size - need larger

I bought a new Dell SE198WFP 19" LCD flat panel monitor yesterday (from Staples) and am struggling to achieve the larger image and font sizes I had on the old 17" flat screen. Basically, they seemed OK when I connected the new monitor. But then I downloaded a new driver for the Nividia GeForce FX 5200 in hopes I would achieve the highest resolution but that was a disaster. The resolution dropped badly and I couldn't adjust it. I finally "rolled back" the driver to (supposedly) the previous driver and that produced a much better appearance. But now I can't seem to get back to the larger image and font sizes I had before.

I have tinkered with the font sizes in the Appearance and Settings tabs under Properties and that has solved most of the font size differences. First, I changed the font size under the Appearance tab to Large but I still had a lot of images that weren't larger so I changed that back to Normal. Then, under the Settings tab, I clicked on Advanced and changed the DPI Setting to 150% of normal. That has increased the size and type size of many things, including some dialog boxes, but it doesn't solve all the differences. I still have many web pages that are significantly smaller than they used to be (overall size and type size) and the Games (Solitaire, etc.) are also much smaller. I can tell that the playing cards are quite a bit smaller. Nothing I do seems to affect them. Yeah, yeah, I know the monitor screen is wider but this is not just a perception problem.

I have a Dimension 4600 running XP. It is about 4 1/2 years old.

Any ideas? Or can you tell me how to "go back in time" for my whole computer. I know what time I did this yesterday and have a vague memory of a tech support guy offering to help me put my computer back to the settings of a certain time in the past. Since I haven't done anything significant on the computer since I messed with the drivers, this might help (maybe).

Thanks for any suggestions!

Cathie