How often do/did you use the computer? Your not as computer illiterate as you say you are…the no air circulation is bad…it’s like not having coolant in your car…eventually…it’ll go boom…in a computers case it’ll go pfffftttttttt. But that can be your problem…something may very well already be burnt out or on it’s last leg. Cold start and it runs for a while…but if you keep removing the battery and putting it back in it constantly shuts off quickly or won’t turn on at all…that little bit of info indicated possible heat damage. Try running it on top of a table or one of those tv dinner stands that everyone seems to own…if you don’t get the problem then the machine was suffocating…if you do get the problem don’t eliminate the cooling problem…just take it a bit further to possible board level damage