You can try something like this:
string input = File.ReadAllText(myfile);
Regex regex = new Regex(@"^(?<col2>.*(?<col1>PR\s*-\s*[A-Za-z0-9-]+).*)$", RegexOptions.IgnoreCase | RegexOptions.CultureInvariant | RegexOptions.Multiline);
MatchCollection matchCollection = regex.Matches(input);
using (TextWriter tw = new StreamWriter(writeFile))
{
foreach (Match m in matchCollection)
{
string col1 = m.Groups["col1"].Value;
string col2 = m.Groups["col2"].Value;
tw.WriteLine("{0},{1}", col1, col2);
}
}
Result
PR-EG4090-28,\\192.168.8.212\c\Avago.ATF.Common\Clotho_SDI_Data\FBAR_2MS5-1505_N3131-3033_PR-EG4090-28_FULL-1PASS_CHAN1_20160610_104333_IP192.168.0.2_G6AABRH