Restore data from old installation

When I use pgAdmin III I cannot connect to the database..an error is
presented: Connection Refused (0x0000274D/10061).

I have not found a solution to this problem and I reinstalled the
package of Postgresql 8.0. I saved the directory of the old
installation.

Now, I should need to have the data inside a database which was stored
in that installation...is there a way through the directory /data? I
tried something but i did not have success...

Please help me!!!! Thanks