No problem with Window 7 Home Premium
In[22]:= $Version
Out[22]= "10.0 for Microsoft Windows (64-bit) (June 29, 2014)"
In[4]:= E^-(10^11)
Out[4]= 1/E^100000000000
In[5]:= E^-(10^10)
Out[5]= 1/E^10000000000
In[8]:= N[E^-(10^11), 100]
Out[8]= 4.7295218355627448338846996370790873689181078443333835968458353849343069\
65812228961404328217878684066*10^-43429448191
In[9]:= N[E^-(10^10), 100]
Out[9]= 9.2785844203248725780731422989302228936631015498327395613504872541681042\
05450822972896290668681753332*10^-4342944820
In[21]:= E^-(10^11) == (E^-(10^10))^(10)
Out[21]= True
