Arduino nano only connects when reset is shorted

good evening everyone

i've recently bought and arduino nano it was working, y tested
it using the blink example
and it worked like a charm
but i soldered the pins and retested
and it was still working
when all of the sudden it disconnected
and it wont reconnect again
unless i short the reset
tested it on both windows 8 and debian jessie
so i cant upload anything to it
when i attempt to i get

avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x30
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x20

tested the loopback and it worked

any suggestions?

thanks in advance