Question:What if my partition is not correct, what happens to my computer? My computer is Windows 98,128ghz, can I install a Windows XP on the computer?
Answer: I'm not sure what you mean about what would happen if your partition is not correct. Either its there or its not. You may have some problems with the partition related to disk errors. If it is giving you problems you can run a thorough checkdisk on it or move the data to another partition and reformat it making sure not to do a quick format. If its your system drive (C) this will not be an option unless you want to reinstall Windows and all of your programs. Also if its not the system drive you can remove the partition completely and recreate it using the Computer Management interface.
For your second question about upgrading from Windows 98 to XP it will depend on your hardware setup. I'm sure it will install and run but most likely it will be so slow that it won't be worth the effort. You say you have 128 GHz so I'm assuming you mean 128 MB of RAM. I recommend 512 MB with a minimum of 256 MB. For your processor I recommend a 1.5 GHz or higher CPU. It's basically up to you to decide on how slow is too slow.