I have a 5G 60Gig iPod I bought about a year and a half ago

There are certain albums (only complete albums) that skip on my iPod. Instead of playing the song, it cycles through the names of the songs without playing them. It slows my iPod down, which it does not respond or responds VERY slowly when I press the Menu key. I have to restart my iPod for it to work normally again.

These files played correctly on my iPod less than two weeks ago, and then suddenly could not play

I have tried everything that I can think of to solve this problem and that includes:
Reformatting the iPod – through Windows explorer and through iTunes
Restoring the iPod with the latest iPod software (through iTunes)
Manually resetting the iPod
Checking the song files to make sure they are not corrupted (They aren’t – they play fine on the computer and also play fine on my MP3 and cell phone)
Checking that the file formats and bitrates are correct for the iPod (They are)
Checking to see that the files are compressed (They are)
Making sure that the files are being converted to be compatible with the iPod (They are)
Running a diagnostic test to make sure the iPod is not corrupted (I don’t think it is)

I have looked at the Apple Support pages and they have not helped.
I googled, but no one seems to have the exactly same problem, and what solved their problems has not helped mine.

Can someone please tell me what to do with it? Thank you!

Okay, so I am trying to recover after a stressful hard-drive reformat. I saved my iTunes library on a flash stick, and now I have loaded it all back into iTunes. The problem is that I can’t get the IPOD software (NOT iTunes – iTunes works great) to work. I had it earlier, but it was in one of those temporary internet files and it expired, I think. So I tried to get it again, and it replaced the old one. Literally, this box came up and saild, "you already have this on your desktop. Do you want to relace it?" Yes, I clicked. Now when I try to open it, this box comes up that called "Windows Installer". It’s got a bunch of weird codes on it and explains display options, install options, repair options and all this weird stuff. When you click okay on at the bottom, nothing happens. I tried getting rid of the software and downloading it again, but it did the same thing.
Can you please help me?