Ed, the original A02 bios release for your Dell laptop was on 6/26/08. A03 was released 7/7/08, and A05 was released 7/31/08. The A06 version released 12/8/08. There haven't been any bios versions released for Windows 7 for that laptop.
If A06 won't install, you can always try one of the earlier versions listed on Dell's site. But bios updates should only be applied to address specific problems on your system. Dell lists all three of the bios updates for your 1535 as "recommended", and not as "critical".
This page Drivers and Downloads
says to download the A06 bios update to your desktop, and then run it from either a Windows or DOS environment per the listed instructions. If you can't run it from the DOS environment, you could always flash the bios from the Windows environment. However, if the power is interrupted during the flash, that could render your system unusuable.
My suggestion is to start a new thread to describe the specific problem(s) you want fixed.