I have installed the new Microsoft Windows 7 64 bit on my Dell Inspiron 1520 Laptop. I can only say that it was worth installing it. Because of the lack of support from Dell (although this laptop is fully 64 bit capable), one has to find some of the drivers itself. I will list here the incompatible drivers that you need, in order for the laptop to work properly with Windows 7 64bit:
1. Missing driver for Ricoh R5C833, R5C847. Corresponding driver can be downloaded here.
2. Synaptics Touchpad / Pointing Stick driver can be downloaded here.
3. Dell Quickset program can be downloaded here.
4. The NVIDIA GeForce 8600M driver can be downloaded from this site. Just download the latest driver, and you are set to go. (Hint: This site and the drivers on it can be actually used for any NVIDIA Graphics card.)
5. If you have problems with the external microphone, or some kind of audio problem, and your audio card is: SIGMATEL STAC 92XX C-Major HD Audio, then please download the driver here.
6. Dell Wireless 355 Bluetooth Module (Bluetooth 2.0 + EDR) can be downloaded here.
7. Intel® Chipset Software Installation Utility for the GM965 mobile chipset can be downloaded here.
8. Intel® Rapid Storage Technology (earlier called Intel(R) Matrix Storage Manager) can be downloaded here.
I hope that this post will help others that encountered the same problems with Dell drivers on their Dell Inspiron 1520, but want to use the new Windows 7 64 bit.