The crap that comes preloaded with many name brand computers will no doubt slow things down…a little bit. However, I think’s it’s possible that you may be blaming a lot of the slowness on Dell’s crapware when it’s not fully to blame (especially if you haven’t reinstalled your operating system in a while). If your computer’s operating system has not been reinstalled in a while, it will begin to become host to all kinds of crud - obsolete registry entries, fragmented hard drive sectors, hidden spyware / viruses, etc. I usually reinstall my operating system about once a year. CCleaner, a good virus scan, and defragmenting your disk can do wonders, but you’ll never get it back to full speed unless you just wipe everything.
If you don’t want to completely redo everything, download CCleaner as per mhendo’s suggestion at http://www.ccleaner.com/download. Also, download a good spyware/virus application and run it. I recommend Malwarebytes Anti-Malware, though there are many other great freeware antivirus/antimalware programs out there. Also, click on the start button at the bottom left of your screen and go to All Programs -> Accessories -> System Tools -> Disk Defragmenter and run that program on your hard drive. This will reorganize the contents of your hard drive to a place where they are more quickly and efficiently accessed.
If you want to completely wipe the mess and start over, remember to BACK UP your important files, because they’re probably going bye-bye. This means photos, documents, music, bookmarked sites, saved games, and something you probably haven’t thought of yet. After you’ve backed everything up, don’t do another thing and GO TO SLEEP. When you wake up in the morning, you’ll remember something you forgot to back up and you’ll be really thankful you didn’t reformat your hard drive the night before. This sounds silly, but I always do this now because I always remember something I forgot the next day.
As for your original question, yes you can reinstall everything with the disk your Dell came with. For that matter, you can reinstall everything with a retail WinXP disk of any variety. Depending on how old the disk is, though, it may not come prepackaged with SP3. If this is the case, it should download automatically if you have automatic updates enabled (I believe that is the default). If for whatever reason it doesn’t download automatically, download from here.
As far as removing the crapware that Dell comes with, try clicking on the Start button in the bottom left hand corner of your screen, then going to Control Panel. Next, click on “Add or Remove Programs”. Look for those pesky programs and uninstall them. Problem solved!
Okay, I’m rambling (I’ve had a few beers), but here’s the meat of my post. Yes, you can reinstall Windows. If you use your Dell disk, the stupid “helpful” programs will still be there, but you can remove them. If you use a retail disk (like you’d find at Wal-Mart, etc.) the programs won’t be there, but don’t shell out $100 if you don’t have one. If you don’t want to reintall Windows, use my tips above. Let us know if you have any further questions and we’ll help you out!