You raise several issues.
1) If you need to boot from a particular drive, just open the BIOS and reset it to point at the particular drive you want as boot drive.
2) Disk fragmentation is a potential cause of slowing the machine, but not nearly so much as the myth suggests. However, you are not going to be able to defrag your drive, unless you delete LOTS of files or are running a tennsy-tiny hard-drive. You report only 200MB free-space on the drive. Defrag requires at least 15% of the drive or it will interrupt the run and not complete.
3) The biggest problem and cause of slow-machine is registry clutter and fragmentation. These result from the way Windows "housekeeps" (or doesn't). There are free downloadable tools that will clean up at least part of your registry, and will at least tell you what is there and needs cleanup (they tell you about it as an incentive to download the non-free version of the tool -- do a search on google for "Registry Mechanic" and "RegistryRepair Pro", which are just two examples of these tools.
4) Continuing about the registry: Adware, spyware, and all sorts of other malware put entries in your registry. You need to get them out. Some of this junk records your keystrokes and sends the data to 'somewhere else' in cyberspace -- interrupting the processes you want running on your machine while it does this, and you perceive it as 'slowdown'. After you run various cleanup tools (I recommend AdAware and Spybot Search & Destroy), and then clean your registry, you will see a real difference in your machine-speed.
5) With only 200MB free-space on your drive, where the heck is the machine putting its virtuality? The answer is that it is putting it on that 200MB -- and reading it back --many, many, many times during even the simplest operations. And with that little space left and that much activity the virtuality write/read DOES have problems with drive fragmentation.
6) You can use the data in your W2000 (Computer Management) MMC to see what this is actually doing to your operation and what else is going on. It ain't pretty. A bigger hard-drive won't really help that much, or for long. You have to make space on your present drive: get rid of a lot of files, defrag, and then MyComputer>(right click)>Properties>Advanced>Performance Options and set your optimization for Applications and make sure your virtual memory paging size is at least 1.5 times RAM and not more than 2.5 times RAM. Compare that requirement to the fact that you presently have only 200MB free-space on the hard-drive -- ie: your virtuality is doing lots of write/read, which is the slowest operation (except printing), and HAS to do it lots of times to do even the simplest task you tell it -- and it has to access and use the registry for every one of those efforts embedded in that task.
Dum vivimus vivamus
