Windows PC can grind to a halt quite quickly if some basic maintenance it not done to them. Approx once a month you should do the following to keep your PC running smooth and trouble free.
1) Run the freely available ccleaner , run both parts, the “Cleaner” and the “Registry” (Always backup changes to the registry part!
2) After cleaning defrag your PC’s hard drive, my favourite tool for this is Auslogic Disk Defrag which is again another FREE tool!
3) Make sure your Anti-Virus software is fully up to date! I am currently running Avira premium, but the free version is good enough for most Home PC installations.
4) Make sure you apply Windows and any other software updates! Windows has the ability to check and update itself, make sure you use it!
Setting up a new pc
As a matter of preference, when I install the Windows OS onto a PC these days, I try and use a 3 
partition system. C drive is my OS, D drive is data (my documents) and T drive is my temporary data. This is getting harder and harder to do now, as Windows likes to take control and place things where it wants. This system works well in my opinion as the OS side of things does not get cluttered up with hundreds of tiny cookie files and rubbish, and your Data is all in one place making it much easier to backup (you do backup don’t you!). Ideally the T drive could be on another disk but only if you have it available, then you know that anything on that drive can pretty much be wiped.
Synchronising PC data
If you run a main PC and a laptop/netbook, I also (used to!) very highly rate Windows Live Mesh which will allow you to keep documents automatically synchronised between the two devices automatically. 
This means I can write some text files on my main pc, then move to my netbook and have the updated/new files there in a matter of moments. I can then continue to work on the files knowing that when I go back to my desktop pc, the newest files are already on there. As a bonus the files are backed up on to the live mesh website as well!
Edit : Windows Live Mesh Beta has been dropped and replaced with Windows Live Mesh 2011. Doesn’t sound very different but the number #1 item in my book, so no more support for Windows XP (Which I run on my netbook). Seems like a very poor decision by MS IMO (Especially as they still support Mac OS!) forcing me to look for another solution. I will be checking out DropBox and reporting back.
