Why won't my iPod charge?

Hi, I've had my 16gb 1st gen iPod touch since November of '07 and just recently it has refused to charge. I have been doing absolutely nothing different -- I plug it into an outlet charger every night so it will be ready to use in the morning. But, for the past two days I have woken up to have it completely dead and it won't charge when I plug it into the outlet or when I plug it into the computer. I have tried switching the USB cords out (we have about 5 at our house) and plugging the outlet charger into different outlets and plugging the computer cord into different USB ports, which makes me think there's a problem with my iPod, especially because I have speakers and a phone charger plugged into the same outlet as my iPod and I have a wireless mouse plugged into the computer as well. Yesterday when it would not charge I restored it and it charged and I figured the problem was over, but it wouldn't charge the next time I tried either. I really don't want to restore it every time I charge it, especially with all the info I have on my iPod -- it takes about 3 hours to restore and get everything back on it.

Also, I've found that if I plug it into a different computer and tape the cord to the iPod so it is constantly pushed in, it charges for the most part... I put it on the computer in this way and when I came home after a seven hour day it was only about 95% charged. (?) Then, I went to restore it with the computer that has the backup on it and during the 3 hours or so when it was restoring I noticed the battery went from full to around half-full... In other words, it's not charging when plugged into the computer once again. I just don't know what to do and I have all my stuff on my iPod, I need it for everything from waking up to busying myself to knowing what I have to do each day to plan out my life.

Any help would be greatly appreciated, thanks!!!!!