Solved Thinkpad SL500 boots into bios rather than Windows

[Gimel]

This is a 2009, but little used laptop. The issue isn't specific to win 7, the problem also occurred with the previous XP installation, but after failing to rectify it on XP, I used it as an excuse to finally get around to installing 7 on it. Wish I'd done that years ago. Other than this it performs excellently, (given the hardware limitations) no glitches or oddities. I've narrowed it down to a combination of running it without the battery installed (not needed, this isn't a portable laptop - it's a hefty brick!) and switching the mains power off overnight. So.... from bios press ESC and then it fully loads win 7 starter within 30 secs. I've played around with the boot order setting the hdd to boot first, but after turning off the mains overnight this setting gets lost and hdd reverts to #3 priority. Startup repair and memory troubleshooting show no errors. CMOS battery? (Where'd all my post formatting go? It contained several paras before posting?)

 

[samuria]

It does indicate cmos battery as it will loose setting so boot to bios

 

[file3456]

Probably the CMOS battery in the laptop for the motherboard to retain BIOS settings. See page 93. https://tim.id.au/laptops/acer/aspire 4820t.pdf

 

[Gimel]

Thanks both for confirming.