I think the question above from AlwaysWilling should have been 'how old is the battery'.
If a year or more, and been frequently used, it is probably the cause of the problem.
Akdos's suggestion in removing /replacing the battery a few times is worth a trying as it will clean any dodgy contacts.
Here in the UK, OEM batteries are reasonable priced. Choose one with a higher wattage, 1 or 2 years guarantee, and same number of cells(generally 6) as the original.
e.g. I have just purchased one for a Toshiba Equium A100 for £12 including postage.
Please advise back on progress.
Good Luck - Keep us posted.
message edited by Mike Newcomb