You should consider upgrading to Windows 7 64 Bit via a clean installation.
See Windows Reinstallation Guide/A Clean Install of Windows 7 which will instruct you in proper installation of Windows 7 and lead to optimum results:
http://philipyip.wordpress.com/dell-community-forums/
Use the following drivers here:
For best results ensure that you have at least 4 GB of RAM but if your model supports 8 GB it is recommended to upgrade to 8 GB of RAM.
The Inspiron 530 is a bit more complicated. There are variants, the Inspiron 530 a/c (http://www.crucial.com/store/listparts.aspx?model=Inspiron%20530a%2Fc) supports a maximum of 8 GB of RAM. The Inspiron 530 b/d (http://www.crucial.com/store/listparts.aspx?model=Inspiron%20530b%2Fd) supports a maximum of 4 GB. If your model is one of the ones that can support 8 GB of RAM than you are best to upgrade to 8 GB. Run the Crucial System Scanner to verify what system you have: http://www.crucial.com/
There are a few reports of running 8 GB on the Inspiron 531, this is unofficial however will likely work: http://answers.yahoo.com/question/index?qid=20111129080330AAFNfmr
In addition a SSD such as the Crucial M500 series for example would be a good addition for either system (upgrade this and install Windows 7 64 Bit on the SSD) and keep your old hard drive for data storage.