Sql Sever Installation Problem In Vista

I am using vista home edition
i already installed vs 2005 standard addition which included sql server express edition also. but due to my unawareness, i uninstalled the sql server. later, i needed it and installed, but by this time, as i was using sql server 2000, i didn't know about sql server management studio and i looked for sql enterprise (as in 2000) , and i installed and uninstalled sql 4-5 times. now i could not install sql server. i searched for some solutions, as in this forum i tried, uppercase computer name(which i already had), and windows installer cleanup utility (but i didn't uninstalled VS 2005). and before using windows installer cleanup utility , my error was
Machine : ANANTA-PC
Product : Microsoft SQL Server 2005 Express Edition
Product Version : 9.2.3042.00
Install : Failed
Log File : c:Program FilesMicrosoft SQL Server90Setup BootstrapLOGFilesSQLSetup0025_ANANTA-PC_SQL.log
Error Number : 1603

and after cleanup utility installed, my error is

TITLE: Microsoft SQL Server 2005 Setup
------------------------------

The installer has encountered an unexpected error. The error code is 2331. Error loading library c:Program FilesMicrosoft SQL Server90Setup BootstrapBin{2AFFFDD7-ED85-4A90-8C52-5DA9EBDC9B8F}sqlca.dll or finding entry point The process cannot access the file because it is being used by another process.
.

For help, click: http://go.microsoft.com/fwlink?LinkID=20476&ProdName=Microsoft+SQL+Server&ProdVer=9.00.3042.00&EvtSrc=setup.rll&EvtID=2331&EvtType=e%3a%5csql9_sp2_t%5csql%5csetup%5cdarwin%5csqlcastub%5cstubredirect.cpp%40Do_LogInstallStart%40launchFunction%40x20


i even tried this link too, their is no useful information, so what may be the problem and what i need to do??