PLease be clear.............you say restart your comp ???? it implies you have some issues regarding oracle installation......if not then simply create a module and call it in form_load
the module should establish the connectivity through use of code.
When you re-start the computer, It takes, some time for Oracle Services to start.. So You have to wait for few minutes after Windows have started..
Also check all the Oracle Services have configured as "Automatic Start"..
'Rem: u will the svrmgr prompt then type CONNECT INTERNAL/ORACLE and hit enter
svrmgr> CONNECT INTERNAL/ORACLE
'After getting the connected message type STARTUP and hit enter
'you get few messages and the database mounted message at end.
'once this is done exit the svrmgr.