By the way, many ISP problems arent the computer or the ISP, but a cheap modem or problems with your phone line.
Many PC's include an el cheapo "winmodem". This is basically enough electronics to interface the computer to an analog line and the main computer processor does all the work itself. A non-winmodem has an onboard processor to do the modem work, and frequently a lot more expensive and sophisticated parts. To be fair, some of the winmodems arent bad, but if you bought it yourself and paid less than $50, its probably only going to give you good speed with very good and very short land line runs. The reported connection speed is complete hogwash, as many modems will report a full speed connection rate and then immediately drop back to something half that or less. At that point, a lesser modem will also retransmit a lot without even telling you.
So one thing you can try if you're unhappy with connection speeds is to go get an external modem in the $100 range and see if your perceived speed is better. You can also go to
www.dslreports.com, click on 'tools' and run the 'speed test' to get something more objective.
Phone lines are also potential problem areas. Even if they're relatively new. Even if you live in a metropolitan area. My old mcmansion was 5 years old when I moved in, all new phone in the area. But they didnt put any waterproof grease on any of the fittings in the phone connections when they installed the lines in the ground, so they started corroding and degrading from day 1. Had to dig up my lawn and the guy across the streets lawn because thats where they decided to bury a main junction. Then it was still flakey because someone had run an extension in the house and hadnt terminated it properly. Then about every six months I could get voice but no reliable data connections out of it. Guy would come out, fiddle in the box down the street, and it'd work another six months. Three years later it turns out that there was a bad card in the box and instead of replacing it the repairman would move my connection to another card, but some maintenance guy would later wonder why that connection was stretched waaay over there and plug me back into the iffy card nobody wanted to replace. One good way to do a high level check on your lines is to connect a plain old $9 analog phone to the modem line, pick up the receiver and press any # except '0'. This will drop the dial tone. Now listen carefully for any clicks, pops, hums or other sounds. If you hear ANYTHING, you've got a bad line. If you find your telephone access box outside the house and open it, you'll find a 'customer access' area with a jack in it. Remove the line plugged in there, which is connecting your house wiring to the telco, plug in your analog phone and repeat the process. If there is still a noise, its in the phone companies "side" of things...if the noise is gone, its in your interior wiring and you probably have to pay to fix it yourself.
I did find an oddball device called a "modem shark" (not a 'shark modem') that was most helpful with not-so-good lines. I was skeptical but it worked. I think I paid about $15-20. Palm sized box with a telephone line-in and line-out plug on either end. Had some filters and caps in it to clean up and stabilize the voltage on the line, couple of other bits and pieces. Basically a low-cost line conditioner. I found even when I was having line troubles the shark seemed to help a lot. I couldnt find any with a 10 second google search, but a little more looking might dig one up.
By the way, I did try the el-cheapo "access4less" ISP I mentioned above, hooked up the mother-in-law on it. $8 connection fee up front and $4.95 a month after that. So far no problems.