There shouldn't be any problem even if you deleted your HOSTS file. In Windows 7, the HOSTS file doesn't even contain anything except remarks. Here's what my Windows 7 HOSTS file contains:
# Copyright (c) 1993-2009 Microsoft Corp.
#
# This is a sample HOSTS file used by Microsoft TCP/IP for Windows.
#
# This file contains the mappings of IP addresses to host names. Each
# entry should be kept on an individual line. The IP address should
# be placed in the first column followed by the corresponding host name.
# The IP address and the host name should be separated by at least one
# space.
#
# Additionally, comments (such as these) may be inserted on individual
# lines or following the machine name denoted by a '#' symbol.
#
# For example:
#
# 102.54.94.97 rhino.acme.com # source server
# 38.25.63.10 x.acme.com # x client host
# localhost name resolution is handled within DNS itself.
# 127.0.0.1 localhost
# ::1 localhost
You may copy the above and paste it on a Notepad and save it as HOSTS but select the Save as type as 'All Files (*.*) and don't put any .txt extension. Just name it plainly as HOSTS and put it in the ETC folder.
If you are using XP you may find a copy of the default HOSTS file here:
http://download.bleepingcomputer.com/misc/host-files/windows-xp/hosts
For Vista:
http://download.bleepingcomputer.com/misc/host-files/windows-vista/hosts
For 7:
http://download.bleepingcomputer.com/misc/host-files/windows-7/hosts